About half of the strokes of a round of golf take place on the greens, where two putts per green is considered good performance. There is an exasperating tendency, even for good players, to upset an otherwise good score by requiring three or more putts after some very respectable fairway shots. Much attention has been given to the design of the putter in an effort to reduce the poor putting performance experienced sooner or later by all players.
Part of the problem centers in the necessarily gentle and slow stroke involved in putting, leaving the muscles of the player plenty of opportunity for erratic behavior without the stablizing affect of club head inertia at high speed. Attempts have been made to make the player more aware of the path of movement of the club head by adding indicia to the top surface. These indicia have included parallel lines and arrows, all perpendicular to the club face. These have been only partially satisfactory. One putter that has been found available to golfers has a head provided with a V-shaped marking on the face, with the axis of the V perpendicular to the face. This marking is positioned with the apex of the V directly at the club face, and is intended to indicate the "sweet spot", which is the common term indicating the center of mass of the putter head.